Polypropylene laminate film

A polypropylene laminate film comprises a crystalline polypropylene layer having laminated on at least one surface thereof a copolymer which is a random copolymer of propylene, ethylene, and an alpha -olefin having at least 4 carbon atoms. The copolymer is obtained by vapor-phase polymerization using a catalyst system comprising (A) a solid catalyst component containing magnesium, titanium and a halogen, (B) an organoaluminum compound, and (C) an electron donative compound in substantially the absence of a liquid medium. The copolymer satisfies the following requirements: (1) ethylene content of 3.0 - 7.0 wt%, (2) alpha -olefin content of 2.0 - 6.0 wt%, (3) ethylene alpha -olefin ratio of at least 1.0, (4) melt flow rate of 10 g/10 minutes or less, (5) ratio of weight average molecular weight: number average molecular weight ratio of 4.5 or less, (6) mp of 135 DEG C or less, and (7) n-hexane-soluble components less than 5.5 wt% The film has excellent low-temperature heat-sealing and hot tack properties, good transparency, and good blocking and solvent resistance.